​The operation details of the double row ball slewing ring can extend the life

As we all know, there is a big difference between standing objects and falling objects. For most seemingly tiny objects, paying attention to the details of the operation of the double-row ball slewing ring can prolong its service life. The following is a detailed introduction to this problem, let’s take a look. It should be noted that the operating details of the double-row ball slewing ring can extend its service life.

First of all, the outer packaging is very clear: usually the packaging of the factory brand is very clear from the line to the color, and it is not fuzzy at all.

Secondly, open the package and check whether the surface of the double row ball bearing is turbid. Please pay attention when purchasing imported double row ball rotary bearings. Because the domestic anti-rust technology is not very mature, it is easy to leave some oil stains on the hands after anti-rust treatment. The imported double-row slewing bearing can smell the anti-rust agent, but the anti-rust oil is almost invisible.

Then, the seal text is clear: Whether there are trademarks on the double volleyball slewing support, such as text, labels, etc., the fonts are small, but most of the products produced by the factory use steel stamping technology, and no heat treatment is performed before the text. Therefore, although the font is small and deep concave, it is very clear. The fonts of the counterfeit products are not only blurred, but the printing process is rough. The fonts float on the surface, and some are easy to wipe off by hand.
Similarly, the chamfer is uniform: the chamfer of the double-row ball slewing bearing is also the position on the horizontal and vertical interface. Due to the limitation of the production process, the bottom of the fake double-row ball slewing bearing has been unsatisfactory in processing.

The final sound: Hold the inner sleeve of the double-row ball bearing body with your left hand, and move the outer sleeve of the double-row ball bearing body with your right hand to rotate it, and listen for noise. Most counterfeit products are produced under poor production conditions and are entirely manual milling operations. Some impurities in the sand will be mixed during the production process. The double-row ball slewing bearing is hidden in the body, and there are impurities on the rotating ring.

Methods of controlling dust:

There are foreign objects such as dust in the reverse branch, and there will be no periodic vibration, dust ring, dust ring size vibration and noise, sometimes not.

The dustproof sound is as follows: For double-row ball slewing bearings/wheel bearings, the method of cleaning the bearings, holes, shafts and some supporting parts before installation is improved and strictly cleaned; by removing foreign matter in the lubricant, the sealing performance of the bearing can be improved. It is forbidden to use impure materials or materials containing foreign bodies in plastics.

Ways to control scar sound:

If the rolling bearing of the double-row ball slewing ring is cracked, jagged or rusted, there will be periodic noise and vibration like rivets. The period is likely to be fixed, but most of it corresponds to the speed, which will appear in a continuous channel. Scars, sometimes scars appear on the steel ball, sometimes no scars, this noise will change with the change of installation and lubrication conditions.

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What are the reasons for the defects of the slewing bearing raceway surface?

The slewing bearing can simultaneously withstand large axial loads, radial loads and overturning moments and other comprehensive loads. It has the characteristics of compact structure, easy to guide rotation, easy installation and easy maintenance. It is widely used in engineering, mining, metallurgy, wind power generation, ships, ports, petroleum, chemical industry, light industry, medical equipment, food, vehicles, robots, etc. , Aerospace, radar, and military industries. Due to installation, working environment and inadequate daily maintenance and other conditions, it is easy to cause defects in the raceway surface. Today, the slewing bearing manufacturer will analyze the reasons for the defects in the raceway surface of the slewing bearing for your reference.

1. Analysis of the causes of spalling on the raceway surface

Due to the serious unevenness or plane distortion of the raceway; after heavy load, the local pressure is too large and exceeds the contact strength of the raceway; due to point impact or long-term overload work, fatigue damage is caused; the raceway is rusted, cracks and gradually expanded; Local strong impact causes the hardened layer to fracture; the hardened layer is uneven or too thin; the harder foreign matter remains in the raceway, which causes the local pressure to be too large; the strip structure in the raw material destroys the hardened layer.

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2. Analysis of the cause of pitting or pitting in the raceway and roller

There are hard debris such as sand and iron filings in the raceway; long-term operation of the local raceway under high contact strength causes local fatigue. Due to poor seal maintenance, rainwater or cleaning fluid is immersed in the raceway, causing local pitting or pitting in the raceway and roller; insufficient or loose assembly bolt pre-tightening force causes the axial gap to increase, and the roller is relatively The large overturning moment rotates, the contact stress on the edge of the raceway increases sharply and slips, and the large stress that the roller actually bears is prone to pitting corrosion.

3. Analysis of the reason for the regular linear indentation on the raceway surface

The main reason is that the slewing bearing is statically vibrating at a fixed position for a long time. For example, when a truck crane travels in a rugged and uneven terrain for a long time, the axial clearance increases, causing the roller bus bar to impact the raceway, resulting in linear indentations with equal spacing.

For precision measuring equipment, in order to improve the anti-overturning rigidity of the turntable bearing, it needs to have a certain negative clearance, which will inevitably bring a quantitative static friction torque, and at the same time, an appropriate static friction torque is also required, which is conducive to reducing Oscillation of small systems. But if the static friction torque is too large, it will also bring undesirable consequences.

In order to prevent excessive static friction torque from appearing, the appropriate selection of negative clearance is important, but at the same time, it is necessary to ensure that the radial fit between the turntable bearing and the turntable and the base has a proper clearance, and pay attention to the installation and fastening methods to avoid distortion of the raceway.

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How to choose the size of school dining table and chairs?

Canteens are very familiar to us. There are canteens in major universities and middle schools. The dining halls that make us remember are the dining tables and chairs. How much do you know about dining hall dining tables and chairs? What are the sizes of dining tables and chairs in the cafeteria?

The school dining table and chair is a kind of dining utensils, and its materials are relatively extensive, mainly based on the style of connecting the tabletop and the chair. It is often used in major colleges and universities, specifically for students and employees to eat. The size of the school dining table and chair should be designed according to its shape. In fact, in life, the school dining table and chair that we have seen are relatively rich in shape, including one-piece, backrest, etc., including four people , Six-person, eight-person, etc. The specifications are: four persons 1200x1650x750 (mm), six persons 1600x1650x750 (mm), eight persons 2000x1650x750 (mm)

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The dining table produced by our company is the mainstream dining table currently used in schools. The appearance is beautiful, the sitting feeling is comfortable, and it is suitable for a wider range of people.

1. The raw materials of the dining table and chairs come from Baosteel and Anshan Iron and Steel high-quality steel, and the quality is effectively guaranteed;

2. The table top is made of stainless steel (with MDF inside), wear-resistant, high-temperature resistant, fire-resistant, beautiful and firm;

3. The table frame is made of high-quality stainless steel square tube, the thickness can be customized to fully meet the needs of customers. The surface of the frame body is treated with degreasing, rust removal and phosphating, special coating electrostatic spraying, high temperature plasticization, and the appearance is flat and beautiful without rust and anti-corrosion. Corrosion, in line with QB/T2383-1998 light industry standard;

4. The gray-white fireproof board tabletop is formed by high-frequency hot pressing once, and the two-side PVC straight edge design is strong and has good bearing capacity;

5. The seat back is made of PP engineering plastic injection molding, with beautiful appearance, comfortable sitting feeling, stable and durable.

Many people say that details determine success or failure, so when dealing with the question of buying restaurant tables and chairs, you must not buy hastily. Before buying, you can contact a reliable manufacturer to discuss this issue. If the price given by the other party can be accepted by you, you can give priority to it. However, the quality of tables and chairs should be the primary consideration in the purchase process.

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How to clean the auditorium soft chairs?

Auditorium soft chairs and theater soft chairs are public seats shared by many people, and they are usually very dirty. How do you clean them in general?

Wipe dry the cotton auditorium soft chairs and cinema soft chairs with a soft cloth, and then dry them. Auditorium soft chairs are used in school auditoriums, multimedia classrooms, and movie theaters. It is a seat with a backrest and some armrests. Most of the auditorium soft chairs are composed of four parts: seat, back, armrests and standing feet. Under normal circumstances, the standing feet and the handrails are integrated to form a firmly installed handrail frame. The composition structure is generally steel-wood structure or steel-plastic structure.

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Cloth maintenance It is forbidden to use wet cloths, hard objects or chemicals such as acids and alkalis to contact the fabrics, so as not to affect the surface quality and service life. If it is stained with beverages or juices, first use a paper towel to absorb the water, then wipe with warm water and neutral detergent, then use a clean soft cloth to dry, and finally dry at low temperature.

General maintenance only needs to use a clean and soft cloth to wipe gently. If you want to clean the dirt produced by long-term use, the most ideal way is: first wipe with a neutral detergent diluted with warm water, and then wrung out with water Wipe off the cleaning liquid with a rag, and finally polish it with a dry cloth. After it is completely dry, wipe it evenly with an appropriate amount of maintenance agent.

The vacuum cleaner is suitable for auditorium chairs and theater chairs made of all materials. The gap between the seat back, armrest and seat surface can be cleaned with a vacuum cleaner. However, when using a vacuum cleaner, do not use a suction brush to prevent damage to the weaving thread on the textile fabric and make the cloth fluffy. It is also necessary to avoid super suction. This may cause the weaving thread to be torn off. Consider using a small The vacuum cleaner to clean.

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Why are auditorium soft chairs becoming more and more popular?

Here are five reasons why high-end auditorium soft chairs, conference hall chairs, lecture hall chairs, and solid wood auditorium chairs are popular.

The auditorium soft chair is a very common seat in our lives. It is very common in all kinds of meeting rooms and auditoriums. Even many people have placed the auditorium soft chair in their own homes. So, why are the auditorium soft chairs so common and popular? Obviously, the auditorium soft chairs must have its own unique features and functions worthy of being appreciated.

Auditorium-chair

Next, we will introduce why the auditorium soft chairs are so popular among people. Mainly include the following aspects:

First: The auditorium’s soft chairs are very practical. The auditorium soft chairs produced on the market now have a multi-functional function, can sit and lie down, have different use values ​​in different environments, and work and rest are not wrong.

Second: The materials used in the auditorium soft chairs are getting better and better, and they look more and more high-end and elegant.

Third: The shape design of the auditorium soft chair mostly uses solid wood, which looks beautiful and generous, the shape is novel and unique, and the decorative effect is very good.

Fourth: The auditorium soft chair has a unique return structure, which can save floor space and space.

Fifth: The structure of the auditorium soft chair is sturdy, durable, not easy to damage, and there will be no problems under normal conditions.

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What are the testing standards for school desk and chair sets?

The quality of school desk and chair sets are related to the health and development of students, so you must pay attention to their materials and dimensions when purchasing. There are many testing standards for school desks and chairs, such as lifting and adjusting mechanisms should have locking devices or limit devices , The parts should be free from damage, and the flap device should be equipped with buffer or damping devices, etc., which can be selected by referring to these testing standards and relevant national standards when purchasing.

school desks and chairs

What are the testing standards for school desks and chairs?

School desks and chairs are used by students, young, active, and in a high-speed period of growth and development, so school facilities and equipment managers need to pay special attention to when choosing desks and chairs for students. Health, hygiene, environmental protection and safety, so what are the safety items for student desks and chairs? What testing standards should students’ desks and chairs meet? The following are some basic items for desk and chair testing, which must be qualified before they can be used:

1. The lifting and adjusting mechanism should be equipped with a locking device or a limit device, which should be flexible, reliable and safe.

2. The gap between the relative moving mechanical device parts and the human body contact part should be ≥25mm.

3. The flipping device should be equipped with a buffer or damping device.

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4. All parts and components should be undamaged.

5. The radius of the rounded corners of the seat surface, chair back and armrests that are in contact with the human body should not be less than 2mm.

6. Some parts that may cause injury should not be accessible to students unless special disassembly tools are used.

7. Desks and chairs should not be disassembled at will, unless special disassembly tools are used.

8. Parts that use lubricating oil should be properly covered.

9. The metal parts should have no unsealed pipe fittings, and the cap should not be easy to fall off.

10. The diameter of all uncovered holes should be ≤5mm or ≥25mm.

11. There should be no burrs, blade corners, sharp edges, penetrating nails, and other sharp objects in the parts in contact with the human body and the parts where items are stored.

In summary, the purchaser must carefully check the relevant standards according to the inspection report to avoid buying unqualified and inferior products that affect the use of students.

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What is the standard for school desk and chair sets

I don’t know if you have a very suitable desk when you study before. For students, a suitable desk is really a very necessary item, especially for children who are studying. So what is the standard for school desk and chair sets?

Desk height standard

Generally, the size of a single desk is about 60CM*110CM, and the height of the table is 71-75CM. The distance between the table and the bottom of the drawer is generally 12.5CM. If it exceeds this distance, people will be hit once they get up. If the desk is a wall-mounted desk, a light trough of about 10 cm can be installed at a distance of about 45 cm from the countertop, and a closet or bookshelf can be set above the light trough, so that the eyes will not be exposed to light. Stimulation can ensure sufficient light.

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Desk height

If you are preparing desks for elementary school students, the height of the desk should preferably be adjustable, so that the desk can be adjusted according to the height of the students, so as to facilitate the healthy development of physical development, and the adjustable height of the desk is the best Control between 53-79CM, the width and depth of the desk top should be controlled between 120CM and 60CM.

In addition, it is best for the desk to be used that even the corners of the desk can be adjusted, because the best angle for writing on the desk is that the desk top can be tilted about 7 degrees, and the tilt angle of the desk when sitting in front of the desk for reading The best is 45 degrees. If the above-mentioned standards can be met, then this desk and chair can be called a standard desk and chair, and its height is also a good height.

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How to repair the school dining table and chair wear?

School dining tables and chairs also play an important role in the field of use and the scope of use. For example, wear resistance, antistatic performance and chemical resistance, etc. Among them, school dining tables and chairs with wear resistance are one of the products with a wide range of applications. So how do we repair the school dining table and chair wear

School dining tables and chairs have two wear methods: chiseling wear and high stress wear. Chiseling wear requires relatively high impact loads on fast food dining tables and chairs.

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It is often used in the fields of ball mill lining, iron forging and lining bricks for vertical kilns. Since the impact force generated is not large, the wear form is mainly chiseling.

Therefore, when selecting materials, the hardness and wear resistance are mainly considered, and the wear resistance is mainly improved, but for high stress wear.

There are relatively high requirements for the hardness of the surface of school dining tables and chairs, to reduce the phenomenon of surface shedding and embrittlement, to resist the pressure caused by abrasives, and to enhance the service life and use effect.

We only understand the wear and tear of school dining tables and chairs. In the actual use process, we can avoid it through some methods to ensure the good use of the product and extend the service life of the product.

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Slewing bearing manufacturer introduction

The slewing bearing is a large support bearing that can bear a comprehensive load, and can bear large axial and radial loads and tilting moments at the same time. This product is generally equipped with mounting holes, internal or external gears, lubrication holes or sealing devices, and has the characteristics of compact structure, light weight, good structural rigidity, stable operation, high precision, safety and reliability.

As a professional slewing bearing manufacturer, Luoyang Longda Bearing Co., Ltd. develops and manufactures various bearing products with an inner diameter of 100mm or more in accordance with national standards, such as large-size, extra-large-size deep groove ball bearings, angular contact ball bearings, etc., with advanced science and technology. , Single row, double row and four row cylindrical roller bearings, spherical roller bearings, single row, double row and four row tapered roller bearings, self-aligning ball bearings, thrust ball bearings, thrust roller bearings, slewing rings, split Bearing. LDB logo, products are widely used in national ports, machine tools, mining, metallurgy, electric power, medical, heavy machinery, coal machinery, cement machinery, petroleum exploration, defense industry and other fields.

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The difference between wheel worm slewing drive and spur gear slewing drive

Worm gear slewing drive and spur gear slewing drive are both highly integrated modular rotary reducers. Users do not need to purchase individual parts one by one and then assemble them into products with worm gear slewing drive and spur gear slewing drive functions. Reduce unnecessary production preparation procedures, greatly improve production efficiency. In a sense, the spur gear slewing drive can replace all toothed slewing bearings. Compared with slewing bearings, it has the advantages of simple installation, easy maintenance, and greater saving of installation space.

So, what are the similarities and differences between the worm gear slewing drive and the spur gear slewing drive in the design and use?

1. Similarities:

Both the worm gear slewing drive and the spur gear slewing drive use the slewing ring as the main moving part. The slewing ring plays the role of driving the equipment to rotate and bearing the equipment load. The worm or gear is used as the driving part of the power input, the housing, the flange, the general support Bearings, seals, etc., as accessories, can finally achieve 360° rotation through reasonable design and assembly, can withstand large loads, and are components with deceleration function. Both types of slewing drives have the characteristics of slewing, deceleration, load-bearing, compact structure, fully sealed, dustproof and waterproof, modular design, and convenient installation and maintenance.

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2. The difference:

1. The worm gear slewing drive uses a worm to drive the slewing support to rotate, and the spur gear slew drive uses a gear to drive the slewing support to rotate.

2. The reduction ratio of the worm gear slewing drive is large, and the reduction ratio of the spur gear slewing drive is small.

In the case of the same modulus and the same outer diameter, the reduction ratio of the worm gear slewing drive is equal to the number of teeth of the slewing ring; the reduction ratio of the spur gear slewing drive is equal to the number of teeth of the slewing ring/the number of gear teeth. The number of teeth of the gear is generally designed to be 15 teeth, and reduce The difference is 15 times.

3. The worm gear slewing drive has the characteristics of reverse self-locking, and the spur gear slewing drive cannot be reversed self-locking.

The worm gear slewing drive can only be driven by the worm to rotate the worm wheel, and the worm cannot be driven by the worm gear to rotate. The reverse self-locking makes the slewing drive widely used in lifting equipment, high-altitude operations and other equipment. Under such working conditions, the worm gear slewing drive is used No braking device is required, and the equipment can remain stationary for a long time without power. The spur gear slewing drive gear can drive the gear ring to rotate, and the gear ring can also drive the gear to rotate in reverse. It cannot achieve reverse self-locking. This feature is also used in some special fields, such as wood grabbers, snow sweepers, etc. Collision cannot be avoided during the use of the equipment, and it does not self-lock when a collision occurs, which acts as a buffer and protects the equipment.

4. The worm gear slewing drive has a low speed limit, and the spur gear slewing drive has a high speed limit.

The worm gear slewing drive is a worm gear drive, and the worm gears slide between each other. High-speed rotation is easy to generate heat, causing the worm to overheat and lock or directly damage. Generally, the rotation speed of the worm gear slewing drive does not exceed 2.5 rpm; gear type slewing drive It is the tooth-to-tooth meshing that works, it is not easy to generate heat, and the speed can usually reach 40-60 rpm.

5. The transmission efficiency of the worm gear rotation drive is low, and the transmission efficiency of the spur gear rotation drive is high.

The worm gear slewing drive has high friction between the worm wheel and the worm, and the transmission energy loss is large, so the transmission efficiency is low, usually only 30%-40%; the friction resistance between the spur gear slewing drive gears is small, and the loss is small, so the transmission efficiency is high. Generally, it can reach 90%-95%, which is very efficient and energy-saving.

6. The worm gear slewing drive has low slewing accuracy, and the spur gear slewing drive has high slewing accuracy.

The rotation accuracy of the ordinary worm gear slewing drive is affected by various factors, and can not achieve a small backlash. Generally, the precision of the precision type can reach within 0.05°; the spur gear rotation drive has high rotation accuracy, and the gears and ring gears can be grounded. The processing method can achieve high precision, and the precision of the gear type rotary drive with a diameter of 1 meter can reach within 0.01°.

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